The Flat Bottomed Head also known as flat cover, is also a common chemical equipment head.Flat Bottom Head geometric shape has circular, elliptic, long circle, rectangle and so on, the most commonly used is circular flat head.Circular plate as a medium pressure, will have two to the bending stress in the plate, So the wall thickness it needs is much larger than the wall thickness of the same diameter cylinder, more bigger than any other head required thickness .The head of pressure bearing equipment does not use flat plate generally, especially the container with larger diameter is not suitable for flat head.Flat head almost used for manholes and hand holes that often need to be removed in pressure vessels, end covers for some heat exchange, blind plates for closed nozzles used during equipment maintenance, etc.